Accuracy of Tibial Nutrient Foramen vs Midshaft Measurement Location for Sex Determination, The

Recently, standard measurements for the Forensic Databank have been changed to measure the diameters of the tibia at the midshaft, rather than at the nutrient foramen. This change may be predicated on intra-person variation in nutrient foramen location and inaccuracy of inter-observer measurement location. This examination assesses the accuracy of determining sex from the two measuring locations-is there a significant advantage to using measurements collected at the midshaft instead of or in addition to nutrient foramen based measurements? Tibial measurements of 400 individuals were collected from the Robert Terry Anatomical Skeletal Collection following the standard osteometric protocols. Data were randomly divided into testing and training sets. Discriminant functions were created in "R" statistical package using left side measurements from the training set. The derived discriminant functions were applied to left only and then left and right measurements in the testing set. Maximum length and proximal and distal epiphyseal breadth, were included in all analyses. Results indicate that proximal and distal epiphyseal breadths were consistently good predictors. Maximum medial-lateral measurement from the crest was a better sex predictor (91.5% correct versus 90% correct). Midshaft minimum diameter and circumference measurements were good sex predictors (88% correct). Combined nutrient foramen and midshaft measurements lost no accuracy (89% correct). The results from this study indicate there is no significant advantage of sex determination based on measurements taken at the nutrient foramen compared to those taken at the midshaft.